“If a passenger from Houston is expecting to fly to New England on Friday or Saturday, there’s a very good chance that their flight will be canceled, or at least delayed.”

Those disruptions could have knock-on effects for the airlines — particularly United, which has taken the lead in canceling flights.

“The airline schedules are such that the airplanes are operated many, many hours out of the day. If an airplane is expected to go to Newark and then is unable to, then the flight the next day can’t depart [from] Newark, cause they don’t have an aircraft. It’ll definitely cost the airlines millions of dollars, and great inconvenience for the passengers.”

Airlines are allowing fee-free changes — and in some cases, refunds — for travel plans upended by the storm.